Ab initio calculation of hydrogen bonding between hydrogen fluoride molecule and hydroperoxy radical: HF·HO 2

Abstract

In this work, we present our new results of the study of hydrogen bonding complexes formed between the hydrogen fluoride and the hydroperoxy radical (HF·HO 2). The structure, vibrational spectrum and binding energy of two energetically low-lying minima (structure1 and 2) are calculated for the first time using UB3LYP and UMP2(FULL) methods. The basis sets used are 6-311++G(d,p), 6-311++G(2d,2p). At all levels of theory, structure 1 ( 2A″) is located as global minimum, with a binding energy D e of about 8.1 kcal/mol. With zero point energy correction, the bonding energy is 5.3 kcal/mol using CCSD(T)//B3LYP method. Structure 2 ( 2A″) is predicted to lie about 1.2 kcal/mol higher in energy, with a hydrogen bonding occurring between the hydrogen atom in the hydrogen fluoride molecule and the terminal oxygen atom in the hydroperoxy radical. The HF stretching frequencies of the HF molecule for structure1 and 2 are red-shifted by 466 and 322 cm −1, respectively, from the isolated molecule. Its infrared intensity is enhanced by 5.4 and 7.3 times that of the monomer respectively.